My credit card was charged $100 for office supplies I ordered online, when the amount I owed was actually $35. The office supply company doesn't respond to my phone calls and emails. What can I do? You did the right thing by using your credit card to make that purchase. Credit cards can offer protections that you don't have if you shop with a debit card. It's often quite easy to enlist your credit card issuer's assistance if you're involved in a dispute..